The invention relates to draglines. A dragline typically includes a main housing movable over the ground, and a boom which extends upwardly and outwardly from the main housing. The upper end of the boom has thereon a sheave mounted for rotation about a horizontal axis. A drag rope extends from a bucket drag mechanism to a bucket for causing horizontal movement of the bucket relative to the boom. A hoist rope extends from a bucket hoist mechanism and over the sheave to the bucket for causing vertical movement of the bucket. More particularly, a dump block is connected to the end of the hoist rope, and a dump rope extends over the dump block sheave and has one end connected to the drag rope and an opposite end connected to the bucket.
The majority of current dump blocks are of a rigid frame design. The dump rope (typically wire rope) cannot be easily removed. One must either first remove a socket from the end of the rope and then slip the rope out of the dump block, or remove an upper pin, spacer(s) and rope guide to get access to the rope. As bucket performance is greatly affected by dump rope length, many mines are wishing to use "pre-socketed" ropes. These ropes come from the factory set at a specific length and with nonremovable socket ends attached. This prevents maintenance crews from either accidentally or intentionally changing the dump rope length and affecting the bucket performance and/or structural loading. In rigging configurations using a dual dump rope, uneven loading occurs if the ropes are not of equal length.
Two solutions to this currently exist in the market. One design uses an upper hood that rotates once a pin/bolt is removed. Sometimes, an upper spacer must also be removed. The hood is attached to the rigging above it and is extremely difficult to maneuver as this rigging weighs many thousands of pounds on all but the smallest of buckets. Another design also allows side access but needs tools (hammer and punch) to remove a pin to allow a heavy door to rotate down out of the way. This design also requires the frame to wrap around the bottom of the dump block so a conventional small pin and bearings may be used. This pin and bearing design is virtually the same as the rigid frame designs in use by many manufacturers and provides virtually no stability to the frame halves. It also creates an excessively heavy frame with the design being nearly twice as heavy as the rigid frame design.